org.gridbus.broker.persistence.db
Class DBReader

java.lang.Object
  |
  +--org.gridbus.broker.persistence.db.DBReader

All Implemented Interfaces:

Reader

public class DBReader

extends java.lang.Object

implements Reader

Author:

krishna

Constructor Summary

DBReader()

DBReader(java.lang.String driver, java.lang.String connectionString, java.lang.String username, java.lang.String password)
Constructor specifying the JDBC driver class name to use

Method Summary

boolean	connect() Sets up the database connection
boolean	disconnect() Closes the database connection
State	read(java.lang.Object brokerID) Reads all the data related to the invocation of the broker with the given brokerID from storage and returns the FarmingEngine as a State object.
State	readBrokerInstance(java.lang.Object brokerID) Same as the read method without an argument, but reads the instance with the given ID
DataFile	readDataFile(java.lang.Object datafileID, java.lang.Object brokerID) Reads the datafile from the store and returns a DataFile object with given ID and brokerID.
boolean	readDataFileHosts(java.util.Collection files, java.util.Collection hosts, java.lang.Object brokerID) Reads the DataHosts and DataFiles and sets the links between them
java.util.Collection	readDataFiles(java.lang.Object brokerID) Reads all the datafiles associated with the given brokerID and returns a collection of datafiles.
DataHost	readDataHost(java.lang.Object datahostID, java.lang.Object brokerID) Reads the datahost from the store and returns a DataHost object with given ID and brokerID.
java.util.Collection	readDataHosts(java.lang.Object brokerID) Reads all the datahosts associated with the given brokerID and returns a collection of datahosts.
java.lang.Object	readEvent(java.lang.Object eventID, java.lang.Object brokerID) Reads the event with the given eventID from the "history" table and returns a BrokerEvent object
java.lang.Object	readEvents(java.lang.Object brokerID) Reads the history of events and returns a collection of BrokerEvent objects
Job	readJob(java.lang.Object jobID, java.lang.Object brokerID) Reads the job with the given jobID and brokerID from the store, and returns a Job object
long	readJobCount(java.lang.Object brokerID)
long	readJobCount(java.lang.Object brokerID, int jobStatus)
java.util.Collection	readJobs(java.lang.Object brokerID) Returns the jobs collection read from the DB.
java.util.Collection	readJobs(java.lang.Object brokerID, int jobStatus) Reads jobs from the persistent storage with the given status, and returns a vector (collection) of jobs with the given brokerID
boolean	readJobVariables(java.util.Collection jobs, java.util.Collection variables, java.lang.Object brokerID) Reads the job-variable values, and sets up the links between them.
java.util.Vector	readNextNJobs(java.lang.Object brokerID, java.lang.String lastJobID, int n) Returns the next 'N' jobs in sequence from the persistent store, if available.
java.util.Vector	readNextNJobs(java.lang.Object brokerID, java.lang.String lastJobID, int n, int jobStatus) If a jobStatus of -999 is passed in, jobs with all statuses are retrieved.
java.util.Vector	readNextNServers(java.lang.String brokerID, java.lang.String lastServerID, int n) Returns the next 'N' servers in sequence from the persistent store, if available.
java.util.Vector	readNextNServers(java.lang.String brokerID, java.lang.String lastServerID, int n, int serverStatus) The status -999 is used to indicate "all" servers.
ComputeServer	readServer(java.lang.Object serverID, java.lang.Object brokerID) Returns the ComputeServer record read from the DB corresponding to the given serverID and brokerID
long	readServerCount(java.lang.Object brokerID)
long	readServerCount(java.lang.Object brokerID, int serverStatus)
java.util.Collection	readServers(java.lang.Object brokerID) Reads all the ComputeServers associated with the given brokerID and returns a collection of servers.
java.util.Collection	readServers(java.lang.Object brokerID, int serverStatus) Reads servers from the persistent storage, and returns a vector (collection) of computeservers with the given brokerID
Task	readTask(java.lang.Object taskID, java.lang.Object brokerID) Reads the task with the given taskID and returns a Task object
java.util.Collection	readTasks(java.lang.Object brokerID) Reads the tasks associated with the given brokerID
Variable	readVariable(java.lang.Object varID, java.lang.Object brokerID)
java.util.Collection	readVariables(java.lang.Object brokerID) Reads the variables associated with the given brokerID

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

DBReader

public DBReader()
         throws java.lang.Exception

Throws:

java.lang.Exception

DBReader

public DBReader(java.lang.String driver,
                java.lang.String connectionString,
                java.lang.String username,
                java.lang.String password)
         throws java.lang.Exception

Constructor specifying the JDBC driver class name to use

Parameters:

driver -

connectionString -

username -

password -

Throws:

java.lang.Exception

Method Detail

connect

public boolean connect()
                throws java.lang.Exception

Sets up the database connection

Specified by:

connect in interface Reader

Returns:

Throws:

java.lang.Exception

disconnect

public boolean disconnect()
                   throws java.lang.Exception

Closes the database connection

Specified by:

disconnect in interface Reader

Returns:

Throws:

java.lang.Exception

readBrokerInstance

public State readBrokerInstance(java.lang.Object brokerID)
                         throws java.lang.Exception

Description copied from interface: Reader

Same as the read method without an argument, but reads the instance with the given ID

Specified by:

readBrokerInstance in interface Reader

Parameters:

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readBrokerInstance(java.lang.Object)

readTasks

public java.util.Collection readTasks(java.lang.Object brokerID)
                               throws java.lang.Exception

Description copied from interface: Reader

Reads the tasks associated with the given brokerID

Specified by:

readTasks in interface Reader

Parameters:

brokerID -

Returns:

Throws:

java.lang.Exception

readVariables

public java.util.Collection readVariables(java.lang.Object brokerID)
                                   throws java.lang.Exception

Description copied from interface: Reader

Reads the variables associated with the given brokerID

Specified by:

readVariables in interface Reader

Parameters:

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readVariables(java.lang.Object)

readJobs

public java.util.Collection readJobs(java.lang.Object brokerID)
                              throws java.lang.Exception

Returns the jobs collection read from the DB.

Specified by:

readJobs in interface Reader

Parameters:

brokerID -

Returns:

collection of job objects (or objects of its subclasses)

Throws:

java.lang.Exception

See Also:

Reader.readJobs(java.lang.Object)

readEvent

public java.lang.Object readEvent(java.lang.Object eventID,
                                  java.lang.Object brokerID)
                           throws java.lang.Exception

Reads the event with the given eventID from the "history" table and returns a BrokerEvent object

Specified by:

readEvent in interface Reader

Parameters:

eventID -

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readEvent(java.lang.Object, java.lang.Object)

readEvents

public java.lang.Object readEvents(java.lang.Object brokerID)
                            throws java.lang.Exception

Reads the history of events and returns a collection of BrokerEvent objects

Parameters:

brokerID -

Returns:

Throws:

java.lang.Exception

readJob

public Job readJob(java.lang.Object jobID,
                   java.lang.Object brokerID)
            throws java.lang.Exception

Reads the job with the given jobID and brokerID from the store, and returns a Job object

Specified by:

readJob in interface Reader

Parameters:

jobID -

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readJob(java.lang.Object, java.lang.Object)

readServer

public ComputeServer readServer(java.lang.Object serverID,
                                java.lang.Object brokerID)
                         throws java.lang.Exception

Returns the ComputeServer record read from the DB corresponding to the given serverID and brokerID

Specified by:

readServer in interface Reader

Parameters:

serverID -

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readServer(java.lang.Object, java.lang.Object)

readVariable

public Variable readVariable(java.lang.Object varID,
                             java.lang.Object brokerID)
                      throws java.lang.Exception

Specified by:

readVariable in interface Reader

Parameters:

varID -

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readVariable(java.lang.Object, java.lang.Object)

readServers

public java.util.Collection readServers(java.lang.Object brokerID)
                                 throws java.lang.Exception

Reads all the ComputeServers associated with the given brokerID and returns a collection of servers. The servers are not associated with jobs by this method, and the jobs have to be explicitly read and set by the caller.

Specified by:

readServers in interface Reader

Parameters:

brokerID -

Returns:

collection of computeserver objects (or objects of its subclasses)

Throws:

java.lang.Exception

See Also:

Reader.readServers(java.lang.Object)

readDataFiles

public java.util.Collection readDataFiles(java.lang.Object brokerID)
                                   throws java.lang.Exception

Reads all the datafiles associated with the given brokerID and returns a collection of datafiles. The datafiles are not associated with DataHosts by this method, and the DataHosts have to be explicitly read and set by the caller, by calling "readDataFileHosts"

Specified by:

readDataFiles in interface Reader

Parameters:

brokerID -

Returns:

collection of datafile objects

Throws:

java.lang.Exception

See Also:

Reader.readDataFiles(java.lang.Object)

readDataFileHosts

public boolean readDataFileHosts(java.util.Collection files,
                                 java.util.Collection hosts,
                                 java.lang.Object brokerID)
                          throws java.lang.Exception

Reads the DataHosts and DataFiles and sets the links between them

Parameters:

files -

hosts -

brokerID -

Returns:

Throws:

java.lang.Exception

readJobVariables

public boolean readJobVariables(java.util.Collection jobs,
                                java.util.Collection variables,
                                java.lang.Object brokerID)
                         throws java.lang.Exception

Reads the job-variable values, and sets up the links between them. Returns true if the operation is successful.

Parameters:

jobs -

variables -

brokerID -

Returns:

Throws:

java.lang.Exception

readDataFile

public DataFile readDataFile(java.lang.Object datafileID,
                             java.lang.Object brokerID)
                      throws java.lang.Exception

Reads the datafile from the store and returns a DataFile object with given ID and brokerID. The datafile is not associated with DataHosts, by this method, and the DataHosts have to be explicitly read and set by the caller by calling "readDataFileHosts"

Specified by:

readDataFile in interface Reader

Parameters:

datafileID -

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readDataFile(java.lang.Object, java.lang.Object)

readDataHosts

public java.util.Collection readDataHosts(java.lang.Object brokerID)
                                   throws java.lang.Exception

Reads all the datahosts associated with the given brokerID and returns a collection of datahosts. The datahosts are not associated with datafiles by this method, and the datafiles have to be explicitly read and set by the caller by calling readDataFileHosts

Specified by:

readDataHosts in interface Reader

Parameters:

brokerID -

Returns:

hashtable containing the datahost names as keys and datahost objects as values

Throws:

java.lang.Exception

See Also:

Reader.readDataHosts(java.lang.Object)

readDataHost

public DataHost readDataHost(java.lang.Object datahostID,
                             java.lang.Object brokerID)
                      throws java.lang.Exception

Reads the datahost from the store and returns a DataHost object with given ID and brokerID. The datahost is not associated with datafiles, by this method, and the datafiles have to be explicitly read and set by the caller, by calling "readDataFileHosts"

Specified by:

readDataHost in interface Reader

Parameters:

datahostID -

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readDataHost(java.lang.Object, java.lang.Object)

read

public State read(java.lang.Object brokerID)
           throws java.lang.Exception

Description copied from interface: Reader

Reads all the data related to the invocation of the broker with the given brokerID from storage and returns the FarmingEngine as a State object. It is the job of the caller to ensure that the objects are in a consistent state.

Specified by:

read in interface Reader

Parameters:

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.read(java.lang.Object)

readTask

public Task readTask(java.lang.Object taskID,
                     java.lang.Object brokerID)
              throws java.lang.Exception

Description copied from interface: Reader

Reads the task with the given taskID and returns a Task object

Specified by:

readTask in interface Reader

Parameters:

taskID -

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readTask(java.lang.Object, Object)

readJobCount

public long readJobCount(java.lang.Object brokerID)
                  throws java.lang.Exception

Specified by:

readJobCount in interface Reader

Parameters:

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readJobCount(Object)

readJobCount

public long readJobCount(java.lang.Object brokerID,
                         int jobStatus)
                  throws java.lang.Exception

Specified by:

readJobCount in interface Reader

Parameters:

brokerID -

jobStatus -

Returns:

the number of jobs with the given status

Throws:

java.lang.Exception

See Also:

Reader.readJobCount(java.lang.Object, int)

readJobs

public java.util.Collection readJobs(java.lang.Object brokerID,
                                     int jobStatus)
                              throws java.lang.Exception

Description copied from interface: Reader

Reads jobs from the persistent storage with the given status, and returns a vector (collection) of jobs with the given brokerID

Specified by:

readJobs in interface Reader

Parameters:

brokerID -

jobStatus -

Returns:

collection of job objects (or objects of its subclasses)

Throws:

java.lang.Exception

See Also:

Reader.readJobs(java.lang.Object, int)

readServers

public java.util.Collection readServers(java.lang.Object brokerID,
                                        int serverStatus)
                                 throws java.lang.Exception

Description copied from interface: Reader

Reads servers from the persistent storage, and returns a vector (collection) of computeservers with the given brokerID

Specified by:

readServers in interface Reader

Parameters:

brokerID -

serverStatus -

Returns:

collection of computeserver objects (or objects of its subclasses)

Throws:

java.lang.Exception

See Also:

Reader.readServers(java.lang.Object, int)

readServerCount

public long readServerCount(java.lang.Object brokerID)
                     throws java.lang.Exception

Specified by:

readServerCount in interface Reader

Parameters:

brokerID -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readServerCount(Object)

readServerCount

public long readServerCount(java.lang.Object brokerID,
                            int serverStatus)
                     throws java.lang.Exception

Specified by:

readServerCount in interface Reader

Parameters:

brokerID -

serverStatus -

Returns:

the number of servers with the given status

Throws:

java.lang.Exception

See Also:

Reader.readServerCount(Object,int)

readNextNJobs

public java.util.Vector readNextNJobs(java.lang.Object brokerID,
                                      java.lang.String lastJobID,
                                      int n)
                               throws java.lang.Exception

Description copied from interface: Reader

Returns the next 'N' jobs in sequence from the persistent store, if available. If no jobs are available, an empty vector is returned.

Specified by:

readNextNJobs in interface Reader

Parameters:

brokerID -

lastJobID - (the ID of the job that was most recently retrieved). If this is null, then it starts from the first job

n -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readNextNJobs(java.lang.Object, java.lang.String, int)

readNextNJobs

public java.util.Vector readNextNJobs(java.lang.Object brokerID,
                                      java.lang.String lastJobID,
                                      int n,
                                      int jobStatus)
                               throws java.lang.Exception

If a jobStatus of -999 is passed in, jobs with all statuses are retrieved.

Specified by:

readNextNJobs in interface Reader

Parameters:

brokerID -

lastJobID - (the ID of the job that was most recently retrieved). If this is null, then it starts from the first job

n -

jobStatus -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readNextNJobs(java.lang.Object, java.lang.String, int, int)

readNextNServers

public java.util.Vector readNextNServers(java.lang.String brokerID,
                                         java.lang.String lastServerID,
                                         int n)
                                  throws java.lang.Exception

Description copied from interface: Reader

Returns the next 'N' servers in sequence from the persistent store, if available. If no servers are available, an empty vector is returned.

Specified by:

readNextNServers in interface Reader

Parameters:

brokerID -

lastServerID -

n -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readNextNServers(java.lang.String, java.lang.String, int)

readNextNServers

public java.util.Vector readNextNServers(java.lang.String brokerID,
                                         java.lang.String lastServerID,
                                         int n,
                                         int serverStatus)
                                  throws java.lang.Exception

The status -999 is used to indicate "all" servers.

Specified by:

readNextNServers in interface Reader

Parameters:

brokerID -

lastServerID -

n -

serverStatus -

Returns:

Throws:

java.lang.Exception

See Also:

Reader.readNextNServers(java.lang.String, java.lang.String, int, int)